Video shows feeding whales from their point of view
To feed, whales use a variety of methods and strategies, and one of the main and most commonly used is bubble feeding, a complex grazing technique used by humpbacks and bryde whales. The whales surround the prey - usually salmon, herring or krills - and start blowing bubbles that end up trapping the fish in a tight circle within the bubble net. It is then that a whale makes the “feeding call” and all swim simultaneously upward and with their mouths open, ready for dinner.
Sounds like a beautiful, complex and efficient process doesn't it? For it was exactly this “ritual” that researchers were able to capture in images. And beautiful pictures. In addition to getting the top shots of this movement, cameras on the whales show the humpbacks' own point of view. “The filming is very innovative. We are watching how these animals are manipulating and preparing their prey for capture. So it is allowing us to come up with new ideas that we really haven't gotten before, "said Lars Bejder, director of the University of Manoa's Marine Mammal Research Program.
He explains that the images provide two angles. In the first, from the perspective of the drone, it is possible to visualize the networks of bubbles, how they begin to surface and how animals pass through it as they arise. Whale cameras, on the other hand, show the animal's perspective, and the overlap of the two data sets “is quite exciting, ” says Bejder.
Camera tags were attached to whales to study behavior
Whale “tactics” are not used by the entire humpback population, as they are not instinctive but learned behavior. For the process to work, cooperation is critical and can include up to 60 whales.
Humpbacks are migratory and spend half of the year in Alaska in food-rich regions, where they are literally “getting fat” and preparing for the journey to Hawaii. The researchers attached camera-equipped suction cup labels to a group of whales in southeastern Alaska - where they feed on bubble nets - to understand this behavior.
“Hawaii is a place of reproduction and rest. Alaska is the foraging site and we are trying to understand how much this migration pattern costs for these animals and also the amount of prey they need to consume to maintain all this migration, ”explains Bejder.
Data collected by whale-loaded cameras, tags that measured acceleration force, and drone are revealing details of how whales perform, how often they feed, and how much they must consume of food to gain enough weight. the breeding season.
The research that highlights and clarifies the behavior of whales is part of an investigation into the possible causes of the drop in humpback numbers. Research takes into account changes in food availability, habitat change and the effects of climate change.